Table 4.
Variations in ventricular repolarization parameters in pre-, within-, and post-desaturation segments in women
| Parameter | Pre-desaturation | Within-desaturation | Post-desaturation |
|---|---|---|---|
| Desaturations without arousals (n = 3,617) | |||
| Mean RR | 857.4 (775.5, 971.8)† | 836.5 (762.3, 943.6)† | 835.6 (759.7, 947.5)† |
| SDRR | 20.4 (12.7, 32.2) | 30.0 (19.4, 45.9) | 24.2 (15.1, 38.6) |
| Mean QT | 410.3 (385.3, 435.3)† | 409.6 (385.7, 434.6)† | 410.1 (385.5, 434.7)† |
| SDQT | 5.5 (3.1, 13.3)† | 7.9 (4.2, 22.8)† | 6.8 (3.7, 22.7)† |
| Mean QTc | 436.8 (424.0, 454.9)† | 440.7 (428.2, 457.5)† | 441.3 (428.4, 459.2)† |
| SDQTc | 8.6 (5.2, 17.6)† | 12.8 (7.8, 27.2)† | 10.5 (6.3, 26.9)† |
| STVQT | 3.9 (2.3, 9.4)† | 5.3 (2.7, 12.1)† | 4.8 (2.6, 12.5)† |
| QTVI | −0.9 (−2.4, 1.0)† | −1.0 (−2.5, 0.8)† | −0.8 (−2.4, 1.0)† |
| Mean Tpe | 83.2 (77.4, 94.4) | 83.5 (77.5, 94.1) | 83.7 (77.4, 94.8) |
| SDTpe | 4.5 (2.7, 12.1)† | 5.7 (3.1, 22.3)† | 5.3 (3.0, 22.0)† |
| Desaturations with arousals (n = 4,948) | |||
| Mean RR | 872.9 (790.3, 974.8)*† | 847.6 (770.2, 936.8)† | 855.4 (775.1, 962.5)*† |
| SDRR | 24.6 (15.7, 38.8)*† | 50.0 (31.6, 74.5)* | 32.6 (19.4, 52.6)*† |
| Mean QT | 406.6 (392.0, 430.9)† | 406.6 (391.6, 429.7)† | 406.9 (391.1, 430.3)† |
| SDQT | 5.5 (3.2, 12.3)† | 9.5 (5.1, 24.8)*† | 6.9 (3.9, 20.2)† |
| Mean QTc | 434.4 (421.8, 450.6)*† | 440.3 (429.1, 454.1)*† | 437.9 (425.2, 453.6)*† |
| SDQTc | 9.2 (5.6, 17.1)† | 18.1 (10.4, 31.2)*† | 12.0 (7.2, 25.7)† |
| STVQT | 3.9 (2.2, 8.5)† | 5.9 (2.9, 12.2)*† | 4.7 (2.6, 11.3)† |
| QTVI | −1.3 (−2.7, 0.4)*† | −1.6 (−3.0, −0.1)*† | −1.4 (−2.8, 0.3)*† |
| Mean Tpe | 83.5 (77.5, 92.6) | 83.8 (78.1, 92.4) | 83.7 (77.9, 93.0) |
| SDTpe | 4.6 (2.8, 12.1)† | 7.1 (3.6, 24.8)*† | 5.3 (3.1, 21.7)† |
Statistical tests were performed using the Wilcoxon signed-rank test. Values are presented as median (interquartile range). Bolded values indicate a statistically significant difference (P < 0.01) compared with the pre-desaturation value. Duration for all parameters except QTVI is presented in millisecond, QTVI is a dimensionless parameter. *Statistically significant difference compared with desaturation events without arousals. †Statistically significant difference compared with men (Table 3). QTc, heart rate corrected QT interval; QTVI, QT variability index; SD, standard deviation; STVQT, short-time variability of QT; Tpe, interval between T-wave peak and T-wave end.